#include "yocto/hashing/md4.hpp"
#include <cstring>

namespace yocto
{
	
	namespace hashing
	{
		
		namespace RFC1320
		{
			/* Constants for MD4Transform routine.
			 */
#define S11 3
#define S12 7
#define S13 11
#define S14 19
#define S21 3
#define S22 5
#define S23 9
#define S24 13
#define S31 3
#define S32 9
#define S33 11
#define S34 15
			
			static const uint8_t PADDING[64] =
			{
				0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
				0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
				0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
			};
			
			/* F, G and H are basic MD4 functions.
			 */
#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define G(x, y, z) (((x) & (y)) | ((x) & (z)) | ((y) & (z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))
			
			/* ROTATE_LEFT rotates x left n bits.
			 */
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))
			
			/* FF, GG and HH are transformations for rounds 1, 2 and 3 */
			/* Rotation is separate from addition to prevent recomputation */
			
			
			
#define FF(a, b, c, d, x, s) { \
(a) += F ((b), (c), (d)) + (x); \
(a) = ROTATE_LEFT ((a), (s)); \
}
#define GG(a, b, c, d, x, s) { \
(a) += G ((b), (c), (d)) + (x) + (uint32_t)0x5a827999; \
(a) = ROTATE_LEFT ((a), (s)); \
}
#define HH(a, b, c, d, x, s) { \
(a) += H ((b), (c), (d)) + (x) + (uint32_t)0x6ed9eba1; \
(a) = ROTATE_LEFT ((a), (s)); \
}
			
			
			/* Encodes input (uint32_t) into output (unsigned char). Assumes len is
			 a multiple of 4.
			 */
			static void Encode( uint8_t *output, const uint32_t *input, const size_t len) 
			{
				size_t i =0, j=0;
				for ( ; j < len; i++, j += 4) {
					output[j]   = (uint8_t)(input[i] & 0xff);
					output[j+1] = (uint8_t)((input[i] >> 8) & 0xff);
					output[j+2] = (uint8_t)((input[i] >> 16) & 0xff);
					output[j+3] = (uint8_t)((input[i] >> 24) & 0xff);
				}
			}
			
			/* Decodes input (unsigned char) into output (uint32_t). Assumes len is
			 a multiple of 4.
			 */
			static void Decode( uint32_t *output, const uint8_t *input, const size_t len) 
			{
				size_t i = 0, j = 0;
				for(; j < len; i++, j += 4)
					output[i] = ((uint32_t)input[j]) | (((uint32_t)input[j+1]) << 8) |
					(((uint32_t)input[j+2]) << 16) | (((uint32_t)input[j+3]) << 24);
			}
			
			/* MD4 basic transformation. Transforms state based on block.
			 */
			static void MD4Transform( uint32_t state[4], const uint8_t block[64] )
			{
				uint32_t a = state[0], b = state[1], c = state[2], d = state[3], x[16];
				
				Decode(x, block, 64);
				
				/* Round 1 */
				FF (a, b, c, d, x[ 0], S11); /* 1 */
				FF (d, a, b, c, x[ 1], S12); /* 2 */
				FF (c, d, a, b, x[ 2], S13); /* 3 */
				FF (b, c, d, a, x[ 3], S14); /* 4 */
				FF (a, b, c, d, x[ 4], S11); /* 5 */
				FF (d, a, b, c, x[ 5], S12); /* 6 */
				FF (c, d, a, b, x[ 6], S13); /* 7 */
				FF (b, c, d, a, x[ 7], S14); /* 8 */
				FF (a, b, c, d, x[ 8], S11); /* 9 */
				FF (d, a, b, c, x[ 9], S12); /* 10 */
				FF (c, d, a, b, x[10], S13); /* 11 */
				FF (b, c, d, a, x[11], S14); /* 12 */
				FF (a, b, c, d, x[12], S11); /* 13 */
				FF (d, a, b, c, x[13], S12); /* 14 */
				FF (c, d, a, b, x[14], S13); /* 15 */
				FF (b, c, d, a, x[15], S14); /* 16 */
				
				/* Round 2 */
				GG (a, b, c, d, x[ 0], S21); /* 17 */
				GG (d, a, b, c, x[ 4], S22); /* 18 */
				GG (c, d, a, b, x[ 8], S23); /* 19 */
				GG (b, c, d, a, x[12], S24); /* 20 */
				GG (a, b, c, d, x[ 1], S21); /* 21 */
				GG (d, a, b, c, x[ 5], S22); /* 22 */
				GG (c, d, a, b, x[ 9], S23); /* 23 */
				GG (b, c, d, a, x[13], S24); /* 24 */
				GG (a, b, c, d, x[ 2], S21); /* 25 */
				GG (d, a, b, c, x[ 6], S22); /* 26 */
				GG (c, d, a, b, x[10], S23); /* 27 */
				GG (b, c, d, a, x[14], S24); /* 28 */
				GG (a, b, c, d, x[ 3], S21); /* 29 */
				GG (d, a, b, c, x[ 7], S22); /* 30 */
				GG (c, d, a, b, x[11], S23); /* 31 */
				GG (b, c, d, a, x[15], S24); /* 32 */
				/* Round 3 */
				HH (a, b, c, d, x[ 0], S31); /* 33 */
				HH (d, a, b, c, x[ 8], S32); /* 34 */
				HH (c, d, a, b, x[ 4], S33); /* 35 */
				HH (b, c, d, a, x[12], S34); /* 36 */
				HH (a, b, c, d, x[ 2], S31); /* 37 */
				HH (d, a, b, c, x[10], S32); /* 38 */
				HH (c, d, a, b, x[ 6], S33); /* 39 */
				HH (b, c, d, a, x[14], S34); /* 40 */
				HH (a, b, c, d, x[ 1], S31); /* 41 */
				HH (d, a, b, c, x[ 9], S32); /* 42 */
				HH (c, d, a, b, x[ 5], S33); /* 43 */
				HH (b, c, d, a, x[13], S34); /* 44 */
				HH (a, b, c, d, x[ 3], S31); /* 45 */
				HH (d, a, b, c, x[11], S32); /* 46 */
				HH (c, d, a, b, x[ 7], S33); /* 47 */
				HH (b, c, d, a, x[15], S34); /* 48 */
				
				state[0] += a;
				state[1] += b;
				state[2] += c;
				state[3] += d;
				
				/* Zeroize sensitive information.
				 */
				memset( x, 0, sizeof(x));
			}
			
			/* MD4 initialization. Begins an MD4 operation, writing a new context.
			 */
			static void MD4Init( MD4_CTX *context )
			{
				context->count[0] = context->count[1] = 0;
				
				/* Load magic initialization constants.
				 */
				context->state[0] = 0x67452301;
				context->state[1] = 0xefcdab89;
				context->state[2] = 0x98badcfe;
				context->state[3] = 0x10325476;
			}
			
			/* MD4 block update operation. Continues an MD4 message-digest
			 operation, processing another message block, and updating the
			 context.
			 */
			static void MD4Update( MD4_CTX *context, const uint8_t *input, const size_t inputLen) 
			{
				unsigned int i, index, partLen;
				
				/* Compute number of bytes mod 64 */
				index = (size_t)((context->count[0] >> 3) & 0x3F);
				/* Update number of bits */
				if ((context->count[0] += ((uint32_t)inputLen << 3))
					< ((uint32_t)inputLen << 3))
					context->count[1]++;
				context->count[1] += ((uint32_t)inputLen >> 29);
				
				partLen = 64 - index;
				
				/* Transform as many times as possible.
				 */
				if (inputLen >= partLen) {
					memcpy( &context->buffer[index], input, partLen);
					MD4Transform(context->state, context->buffer);
					
					for (i = partLen; i + 63 < inputLen; i += 64)
						MD4Transform(context->state, &input[i]);
					index = 0;
				}
				else
					i = 0;
				
				/* Buffer remaining input */
				memcpy( &context->buffer[index],  &input[i], inputLen-i);
			}
			
			/* MD4 finalization. Ends an MD4 message-digest operation, writing the
			 the message digest and zeroizing the context.
			 */
			static void MD4Final(uint8_t digest[16], MD4_CTX *context) 
			{
				uint8_t bits[8];
				size_t index, padLen;
				
				/* Save number of bits */
				Encode(bits, context->count, 8);
				
				/* Pad out to 56 mod 64.
				 */
				index = (size_t )((context->count[0] >> 3) & 0x3f);
				padLen = (index < 56) ? (56 - index) : (120 - index);
				MD4Update(context, PADDING, padLen);
				
				/* Append length (before padding) */
				MD4Update (context, bits, 8);
				/* Store state in digest */
				Encode(digest, context->state, 16);
				
				/* Zeroize sensitive information.
				 */
				memset(context, 0, sizeof(MD4_CTX));
				
			}
			
		} // RFC 1320
		
		md4::md4() throw() : function(__length, __window), ctx()
		{
		}
		
		const char *md4:: name() const throw()
		{
			return "MD4";
		}
		
		
		void md4:: set() throw()
		{
			RFC1320::MD4Init( &ctx );
		}
		
		void md4:: run( const void *buffer, size_t buflen ) throw()
		{
			assert( !(buflen>0&&NULL==buffer) );
			RFC1320::MD4Update( &ctx, (const uint8_t *)buffer, buflen );
		}
		
		void md4::get(void *output, size_t outlen ) throw()
		{
			assert( !(output==NULL&&outlen>0) );
			uint8_t  digest[16];
			RFC1320::MD4Final( digest, &ctx );
			fill( output, outlen, digest, sizeof(digest) );
		}
		
		md4:: ~md4() throw()
		{
			memset( &ctx, 0 , sizeof(ctx) );
		}
		
		
	}
	
}

